Why it might not be starting:
* Passive Anti-Theft System (PATS): 1991 Camaros might not have a fully electronic PATS system like later models, but they could have a rudimentary system involving the ignition switch and possibly the key itself. Simply replacing the ignition cylinder doesn't automatically reset or bypass any anti-theft mechanisms. The new cylinder might not be correctly matched to the car's system.
* Incorrect Cylinder Installation: Even a seemingly perfect fit might have subtle misalignments preventing proper communication with the car's system.
* Damaged Wiring: During the ignition cylinder replacement, you might have accidentally damaged some wiring related to the ignition system or the anti-theft system.
* Faulty Key: While you think it has a transponder chip, the chip might be damaged or not properly programmed for your car. Just because it *looks* like it has a chip doesn't guarantee it's functional.
* Other Ignition Issues: The problem might be unrelated to anti-theft. A faulty ignition switch, neutral safety switch, or other components could prevent the car from starting.
Troubleshooting Steps:
1. Verify Key Functionality: If possible, try a different key known to work in the car (if you have a spare). This helps isolate whether the issue lies with the key, the cylinder, or the car's system.
2. Check for Damaged Wiring: Carefully inspect all the wiring around the ignition cylinder for any breaks, loose connections, or signs of damage. Repair or replace any damaged wiring.
3. Recheck Cylinder Installation: Make absolutely sure the ignition cylinder is properly seated and aligned. Consult a repair manual or online resources for your specific model year to ensure correct installation.
4. Neutral Safety Switch: This switch prevents the car from starting unless the transmission is in Park (or Neutral, depending on the transmission). Check to ensure this switch is working correctly.
5. Professional Help: If you've checked all the above and the car still won't start, it's strongly recommended to take it to a qualified mechanic or locksmith specializing in older vehicles. They have specialized tools and knowledge to diagnose and fix potential problems with the ignition system and anti-theft mechanisms. They may be able to program a key properly or identify other faults.
Important Note on "Resetting" Theft: There's no simple "reset" button for a 1991 Camaro's anti-theft system. The system is integrated into the car's electronics and usually requires specialized tools and knowledge to access.
In summary, while it *could* be an anti-theft issue, there are other mechanical causes that need to be investigated first. Don't jump to conclusions. Systematic troubleshooting is key to finding the solution.
